Damper assembly

ABSTRACT

A damper assembly comprises a driving member, a coil spring, a driven member drivable by the driving member via the coil spring, and dividers by which the coil spring is divided. Relative rotation between the driving member and the driven member via the coil spring is limited by engagement between at least one of engageable portions arranged on the driving member and its corresponding one of engageable portions arranged on the driven member. The damper assembly may additionally comprise an intermediate member arranged for relative rotation between the driving member and the driven member and formed integrally with the dividers. The intermediate member is provided with two sets of similar engageable portions such that relative rotation between the driving member and the intermediate member and relative rotation between the intermediate member and the driven member are limited by engagement between at least one of the engageable portions of the driving member and its corresponding one of one of the sets of engageable portions of the intermediate member and by engagement between at least one of the other set of engageable portions of the intermediate member and its corresponding one of the engageable portions of the driven member.

BACKGROUND OF THE INVENTION

[0001] a) Field of the Invention

[0002] This invention relates to a damper assembly to be disposed between an engine and a transmission, especially to a damper assembly a coil spring of which is protected from permanent setting in fatigue or breakage.

[0003] b) Description of the Related Art

[0004] In a conventional damper assembly, a driven member is driven via a coil spring by a driving member connected directly to an engine. This conventional construction is accompanied by an unavoidable drawback that due to over-loads applied by combustion in the engine, the coil spring is repeatedly compressed fully with all coils brought into contact with adjacent coils, resulting in permanent setting in fatigue or breakage.

SUMMARY OF THE INVENTION

[0005] With the foregoing in view, the present invention has as a primary object the provision of a damper assembly a coil spring of which is protected from permanent setting in fatigue or breakage.

[0006] In one aspect of the present invention, there is thus provided a damper assembly comprising:

[0007] a driving member,

[0008] a coil spring,

[0009] a driven member drivable by the driving member via the coil spring, and

[0010] dividers by which the coil spring is divided into plural spring sections;

[0011] wherein relative rotation between the driving member and the driven member via the coil spring is limited by engagement between at least one of engageable portions arranged on the driving member at predetermined locations and its corresponding one of engageable portions arranged on the driven member at predetermined locations.

[0012] The damper assembly may further comprise:

[0013] an intermediate member arranged for relative rotation between the driving member and the driven member and formed integrally with the dividers,

[0014] wherein relative rotation between the driving member and the intermediate member via the coil spring and relative rotation between the intermediate member and the driven member are limited by engagement between at least one of engageable portions arranged on the driving member at predetermined locations and its corresponding one of a first set of engageable portions arranged on the intermediate member at predetermined locations and by engagement between at least one of a second set of engageable portions arranged on the intermediate member at predetermined locations and its corresponding one of engageable portions arranged on the driven member at predetermined locations, respectively.

[0015] Owing to the above-described construction, the coil spring is limited in coil angle whenever a predetermined load or a load greater than the predetermined load is applied. This limitation makes it possible to protect the coil spring from over-loads and hence, from permanent setting in fatigue or breakage without requiring additional parts. With a minimized increase in the manufacturing cost, the coil spring can therefore be protected from permanent setting in fatigue or breakage.

[0016] Preferably, the damper assembly may be effectively sealed within a hollow space formed by a front cover and rear cover, which are fixedly secured on the driving member, and a retainer cover plate. The hollow space is filled with a viscous medium such that viscous damping resistance is applied to relative motion between the coil spring and the driven member (and the intermediate member if any). This preferred embodiment makes it possible to effectively reduce wear and noise which occur between the associated members.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings, in which:

[0018]FIG. 1 is a front view of a damper assembly according to a first embodiment of the present invention, in which parts of members are successively cut off;

[0019]FIG. 2 is a cross-sectional view of the damper assembly according to the first embodiment of the present invention, taken in the direction of arrows II-II of FIG. 1;

[0020]FIG. 3 is a front view of the damper assembly according to the first embodiment of the present invention when operated to maximum extent;

[0021]FIG. 4 is a front view of a divider ring in the damper assembly according to the first embodiment of the present invention;

[0022]FIG. 5 is a similar front view as FIG. 1, and shows a damper assembly according to a second embodiment of the present invention;

[0023]FIG. 6 is a cross-sectional view of the damper assembly according to the second embodiment of the present invention, taken in the direction of arrows VI-VI of FIG. 5;

[0024]FIG. 7 is a similar front view as FIG. 3, and illustrates the damper assembly according to the second embodiment of the present invention when operated to maximum extent;

[0025]FIG. 8 is a front view of a drive plate in the damper assembly according to the second embodiment of the present invention;

[0026]FIG. 9 is a front view of a hub in the damper assembly according to the second embodiment of the present invention; and

[0027]FIG. 10 is a cross-sectional view of the hub in the damper assembly according to the second embodiment of the present invention, taken in the direction of arrows X-X of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

[0028] Referring first to FIGS. 1 through 4, a description will be made of the damper assembly 10 according to the first embodiment of the present invention. Illustrated in these drawings are a front cover 1, a rear cover 4, a drive plate 3 directly connected to a power output shaft of an engine, a retainer cover plate 4, a retainer plate 5 drivable by the drive plate 3 via coil springs 80, a hub 7 fixedly secured on the retainer plate 5 by means of rivets 11, and a divider ring 6 dividing the coil springs 80 into plural spring sections. The divider ring 6 is arranged movably to predetermined extent relative to the hub 7.

[0029] Also depicted are spring pockets 31 formed in the drive plate 3, shoulders 32 formed on the drive plate 3 at predetermined positions, and spring seats 33 formed on the drive plate 3. Designated at numeral 51 are spring seats formed on the retainer plate 5. Between each spring seat 51 and its corresponding spring seat 33 of the drive plate 3, pressing action is performed via the associated coil spring 80.

[0030] In the illustrated first embodiment, the drive plate 3 corresponds to a driving member, the retainer plate 5 and hub 7, in combination, corresponds to a driven member, and the divider ring 6 corresponds to an intermediate member.

[0031] Each coil spring 80 is divided by a corresponding tab 61 of the divider plate 6 into spring portions. In the illustrated embodiment, there are three sets of coil springs 80 between the drive plate 3 and the retainer plate 5. These three sets of coil springs 80 are divided by the three tabs 61 of the divider ring 6, respectively, so that there are six sub-sets of coil springs in total. In the illustrated embodiment, each coil spring 80 is constructed of a triple spring which is in turn formed of an outermost spring 81, a middle spring 82 and an innermost spring 83. The drawings also show mounting rivet bores 21, positioning bores 22, and welds 23.

[0032] The division of coil springs 80 has made it possible to use shorter coil springs. In addition, even if the individual sub-sets of the coil springs are linear springs, they can be arranged along a circle as depicted in the drawings. This assures smooth and accurate spring action.

[0033] It is to be noted that in the drawings, the damper assembly rotates in the direction of arrow R (i.e., counterclockwise). When the drive plate 3 rotates upon receipt of an engine output, the drive plate 3 drives the retainer plate 5 via the coil springs 80 and the divider ring 6, and also drives the hub 7 fixedly secured with the retainer plate 5. Power is then outputted through a power output shaft connected to the hub 7 via splines 73.

[0034] In this first embodiment, the front cover 1 and the rear cover 2 are fixedly secured at the welds 23 with the drive plate 3 as a driving member, and the retainer cover 4 is fixedly secured on the retainer plate 5, so that the damper assembly is effectively sealed with a hollow space formed therein. The hollow space is filled with a viscous medium, such as grease or oil, as a lubricating oil. This viscous medium applies viscous damping resistance to relative motions among the coil springs, the divider ring 6 as an intermediate member and the retainer plate 5 as a driven member to effectively reduce wear and noise.

[0035] In FIG. 3, the damper assembly has been operated to the maximum extent. To protect each spring from permanent setting in fatigue or breakage by preventing the spring from being fully compressed with all coils brought into contact with adjacent coils, the shoulders 32 of the drive plate 3 are brought into contact with shoulders 62 arranged on the tabs 61 of the divider ring 6, and shoulders 64 arranged on tabs formed on an inner circumference of the divider ring 6 are brought into contact with shoulders 72 formed on an outer circumference of the hub 7. As a result, the drive plate 3, the divider ring 6, the retainer plate 5 and the hub 7 are prevented from any further relative rotations. Accordingly, the springs are not compressed any further.

[0036] Referring next to FIGS. 5 through 10, a description will be made of the damper assembly 10 according to the second embodiment. A drive plate 3 in the damper assembly of the second embodiment has spring pockets 35, spring seats 36, a central bore 37, tabs 38, and shoulders 39 (see FIG. 8).

[0037] A spring dividing means as an intermediate member is not such a divider ring as in the first embodiment, but is formed as dividers 65 received in the spring pockets 35, respectively. The second embodiment is similar in the remaining fundamental construction to the first embodiment. In FIGS. 5 and 6, those parts of the damper assembly which are the same or equivalent to corresponding parts in FIGS. 1 and 2 are shown by the same reference numerals and are not described further.

[0038] In FIG. 7, the damper assembly has been operated to the maximum extent as in FIG. 3. Upon receipt of an engine output, the drive plate 3 pushes the unit of the retainer plate 5 and hub 7, as a driven member, in the direction of arrow R via the coil springs 80 and the dividers 65. If the load reaches a predetermined value or greater, the shoulder 39 of the drive plate 3 are brought into contact or engagement with the shoulders 72 of the hub 7 so that the coil springs 80 are protected from further compression.

[0039] This application claims the priority of Japanese Patent Application 2000-274323 filed Sep. 11, 2000, which is incorporated herein by reference. 

1. A damper assembly comprising: a driving member, a coil spring, a driven member drivable by said driving member via said coil spring, and dividers by which said coil spring is divided into plural spring sections; wherein relative rotation between said driving member and said driven member via said coil spring is limited by engagement between at least one of engageable portions arranged on said driving member at predetermined locations and its corresponding one of engageable portions arranged on said driven member at predetermined locations.
 2. A damper assembly according to claim 1, wherein said engageable portions of said driving member are arranged on tabs formed on an outer or inner circumference of said driving member, said engageable portions of said driven member are arranged on tabs formed on an inner or outer circumference of said driven member, and said at least one engageable portion of said driving member and said corresponding engageable portion of said driven member are brought into engagement with each other by relative motion between said driving member and said driven member.
 3. A damper assembly according to claim 1, wherein said driving member is provided with at least one tab formed on an outer or inner circumference of said driving member and having two engageable portions arranged with a predetermined interval therebetween on said tab, and said driven member is provided with at least one tab formed on an inner or outer circumference of said driven member and having two engageable portions arranged with a predetermined interval therebetween on said tab.
 4. A damper assembly according to claim 1, wherein said damper assembly is effectively sealed within a hollow space formed by a front cover and rear cover, which are fixedly secured on said driving member, and a retainer cover plate; and said hollow space is filled with a viscous medium such that viscous damping resistance is applied to relative motion between said coil spring and said driven member.
 5. A damper assembly according to claim 1, further comprising: an intermediate member arranged for relative rotation between said driving member and said driven member and formed integrally with said dividers, wherein relative rotation between said driving member and said intermediate member via said coil spring and relative rotation between said intermediate member and said driven member are limited by engagement between at least one of engageable portions arranged on said driving member at predetermined locations and its corresponding one of a first set of engageable portions arranged on said intermediate member at predetermined locations and by engagement between at least one of a second set of engageable portions arranged on said intermediate member at predetermined locations and its corresponding one of engageable portions arranged on said driven member at predetermined locations, respectively.
 6. A damper assembly according to claim 5, wherein said engageable portions of said driving member are arranged on tabs formed on an inner or outer circumference of said driving member, said first set of engageable portions of said intermediate member are arranged on tabs formed on an outer or inner circumference of said intermediate member, said second set of engageable portions of said intermediate member are arranged on tabs formed on said inner or outer circumference of said intermediate member, said engageable portions of said driven member are arranged on tabs formed on an outer or inner circumference of said driven member, said at least one engageable portion of said driving member and said corresponding one of said first set of engageable portions of said intermediate member are brought into engagement with each other by relative motion between said driving member and said intermediate member, and said at least one of said second set of engageable portions of said intermediate member and said corresponding one of said engageable portions of said driven member are brought into engagement with each other by relative motion between said intermediate member and said driven member.
 7. A damper assembly according to claim 5, wherein said driving member is provided with at least one tab formed on an inner or outer circumference of said driving member and having two engageable portions arranged with a predetermined interval therebetween on said tab; said intermediate member is provided with at least one tab formed on an outer or inner circumference of said intermediate member and having two engageable portions arranged with a predetermined interval therebetween on said tab and is also provided with at least one tab formed on an inner or outer circumference of said intermediate member and having two engageable portions arranged with a predetermined interval therebetween on said tab; and said driven member is provided with at least one tab formed on an outer or inner circumference of said driven member and having two engageable portions arranged with a predetermined interval therebetween on said tab.
 8. A damper assembly according to claim 5, wherein said damper assembly is effectively sealed within a hollow space formed by a front cover and rear cover, which are fixedly secured on said driving member, and a retainer cover plate; and said hollow space is filled with a viscous medium such that viscous damping resistance is applied to relative motions among said coil spring, said intermediate member and said driven member. 